opengl - 1k vs 4k texture resolution performance impact -

this realtime graphics.

let's there single mesh rendering. place 1k (1024x1024) texture on , renders fine. let's place 4k texture on render 1k section of texture using different uvs on same mesh.

now both times, visible surface has 1k texture on it. 1 comes 1k texture map other 4k texture map. there difference in performance, not counting increased vram usage 4k map.

for intents , purposes, no, there no difference.

by restricting uvs top left 1024x1024 you'll pulling in same amount of texture data if texture 1024x1024 , read entire thing. number of texture samples remains same well.

it's impossible rule out of course without having low-level knowledge of every gpu past, present , future, should assume performance same.